Plural-stage heater



Feb. 7, 1928.

c w. STANCL IFFE PLURAL STAGE HEATER Filed Aug; 24. 1923 WMM 2% igs Patented Feb. 7, 1928.

UNITED. STATES PATENT OFFICE.

CECIL W. STANCLIFFE, 0F NEVJ YORK, N. Y., ASSIGNOR TO STANCLIFFE ENGINEERING CORPORATION, OF NEW YORK, N. Y., A

CORPORATION OF NEW YORK.

PLURAL-STAGE HEATER.

Application filed. August 24, 1923. Serial No. 659,073.

The present invention relates to means for heating fluids progressively in a series of stages. Such heaters may be applied to a wide Variety of purposes including that of heating feed water for boilers, of distilling oils and other mixtures of liquids which are capable of being separated by distillation, etc. One purpose of heating such liquids in a number of stages is to avoid certain harmful effects which may take place if the fluid is heated to a given temperature in one stage. For example, take the case of heating feed water for boilers. In many locations where steam boilers are used the water available for feeding them contains salts in solution and earth matters in suspension. Different ones of these substances are precipitated or deposited when the water is heated to respectively different temperatures, and some times the solid matters which settle out of the water when heated to a moderate degree hecome baked into a hard scale when the water is heated to a degree necessary for precipitating other suspended or dissolved foreign matter, or when heated to the temperature to which it should be brought for greatest eflicienc and economy before being put into the boiler. In such circumstances, if the matter deposited or liberated from the water at a moderate degree of heat can be removed while it is still in a pulverulent or fluid state and before the water has been heated to the degree which would harden such deposits, much trouble and damage, both to the heater and to the boiler, may be avoided.

Again, in the distillation of oil, for in stance, and particularly in the use of methods which involve cracking of the oil, trouble is encountered from carbon deposits which form on the tubes of the heating units and cause loss of efficiency with liability to disaster due to failing of the tubes which are thus encrusted or stopped up by carbon.

It is a part of myobject to furnish a heating apparatus in which the water, oil or other fluid to be heated or distilled, can be heated in successive stages to different temperatures and with control of temperature at each stage, and to provide such an apparatus with means by which solid deposits and/or gases can be removed between stages of the heating process and before they have had opportunity to adhere to the tubes or passages or other interior parts of the apparatus. Another part of, my object is to furnish a plural stage heater with means by which the internal passages thereof can be readily cleaned.

In principle the complete apparatus involves a plurality of heat interchanger units, having passageways for conduction of the fluid to be heated, combined with means for applying heating fluids, eitherthe same or different fluids, at different temperatures to the several units, and means for collecting and removing deposits of solid matter er gases between successive units. Preferably the units referred to are made accordin to the invention disclosed in my Patent Nd. 1,571,068, dated January 28, 1926, which comprises, essentially, a body of solid heatconducting material having sets oftubes or passageways extending in different directions, transverse to oneanother, through it.

The present invention, indeed, involves one phase ofthe disclosure set forth in the said prior patent. consisting of a plurality of units associated in series, with provisions for causing one fluid to pass in series through the assembled units, and separate means for causing another fluid or fluids to pass through the individual units. As to the subject-matter just mentioned, the present application is a continuation of that on which my prior patent, above identified was issued.

, In the drawings, the single figure represents diagrammatically a plural stage heater embodying the present invention and including as the heat interchanger units there of the interchanger disclosed in the aforesaid patent.

In order to simplify the description of construction and operation, I will assume, for the present, that the apparatus here illustrated is provided to, heat boiler feed water and is composed of four units, with accessory coupling means adapted to heat the water in four stages. As will later morefully appear, this assumption is merely typical and illustrative.

The heat interchanger units of this apparat-us are indicated as A, B, C and D. They are substantially alike in principle, and like the heat interchanger unit disclosed in my prior patent before mentioned. That is, each comprises a series of tubes or passages 10 extending in one direction, in this instance the vertical direction, and another series of tubes or passages ll extending in a differcut direction, in this instance horizontally. The tubes or passages of each series are preferably parallel to one another and are arranged in rows which alternate with the rows of passages of the other set.

The units may be constructed by embedding tubes, with the arrangement desired, in fusible metal, leaving solid masses of metal at the corners or sides of the block for attachment of additional fittings, or by drilling holes through a solid block of metal, or by molding metal around cores in such manner as to form the desired passages when the cores are removed, all as disclosed in said prior patent, or by building up perforated bars or blocks into a unit as disclosed in my pending application Ser. No. 660,139, filed concurrently herewith.

The several units are assembled in series with intermediate receivers 12, 13 and 14 and with end'fittings 15 and 16 forming terminal chambers. The chambers enclosed by these various fittings open into the horizontal tubes of the various units, and the end fittings have connections 17 and 18, respectively, for admission and eduction oi the fluid to be heated.

At the top and bottom of the individual units are fittings 19 and 20 which enclose chambers opening into the ends of the vertical tubes 10 and have connections 21 and 22 for admission and exhaust of heating fluids. Connections 23 and 2% similar in principle, but of specifically different design, are connected to the unit D and typify a special conduit for conveying waste furnace gases through that unit. It is to be understood, however, that since this illustration is di agrammatic, the fittings and connections may, in practice, be of various specific characteristics adapted to the particular fluid which is applied for heating one or another of the unit V It'is to be understood that the various fittings thus described as connected with the units may be constructed in detail as shown and indicated in my prior patent, and it is further to be understood that they may be of the special character therein disclosed which is adapted to permit opening of the fittings, without disturbing the fluid connections, for the purpose of giving access to the passageways so that said passageways can be cleaned. With the purpose of cleaning in view, the units are preferably arranged with their horizontal passageways all in alinement to permit access to all of them by cleaning tools when either of the end fittings is opened.

In the top and bottom of the intermediate receiving chambers are connections 25 and 26 for the release of air or other gases and vapors, and sludge, respectively. The connections 26 are shown as provided with valves 27. and the connections 25 may equals ly be provided with valves if desired. So

also may all or any of the other fittings pre viously described. Valves may be placed in any of these connections in any situations where they may be useful to control the admission and flow of the fluid being heated, or the admission and flow of the heating fluids.

For the purposes of a feed water heater it may be considered that the first section or unit A is heated bycondensate, the second unit by exhaust steam, the third unit by live steam, and the fourth unit by flue gases. These are illustrative or typical heating media having different temperatures.

The water flowing through the pasageways of any unit is given certain velocity determined by the rate at which the water is admitted to the heater. But in each of the intermediate receivers. the area of which is greater than the combined areas of the flow passages in the heating units, and may be made as much greater as desired, the velocity of the water is checked and opportunity given for it to flow in'eddies and to become still. In the successive receivers solid matter which is carried in suspension by the water, and dissolved minerals whichare precipitated by heat, are allowed to settle out, after the water has passed through the particular unit in which the precipitation of any specific mineral occurs. While the velocity of flow through the passages of the heating units is great enough to remove deposit of solid matter by the scouring action of the water, the slower velocity in the receiving chambers allows the solid matter to settle. It is then removed through the sludge outlets. Air or other gases which may separate from the water in the course of heating may be blown off through the gas outlets 25. Opportunity is thus given for removal of precipitate immediately after each stage'of the heating in which precipitation occurs.

The independent means for separately conducting heating media to the difierent units permits a wide range of selection and control as to the heating medium used inany unit and as to the temperature of such medium. I may regulate these various temperatures according to the character of the water being heated in order most fully'and eificiently to remove the foreign matters con-' tained therein which would be detrimental to a steam boiler'by depositing scale on the heating surfaces of the boiler.

For other uses than heating feed water, such as that of crackingand distilling oil, the selection and control of heatingmedia in the several units of the apparatus enable the various constituents of the oil, etc., to be cracked and separated from other constituents with the minimum deposition of carbon: and the rapid flow of the fluids being. distilled through the passageways; re-

moves. by scouring action, any carbon which may be deposited in those passageways. Then, with slowing down of the flow of the fluid in the receiving chambers, the carbon is allowed to settle out in such chambers, and precipitated carbon can be readily removed through the sludge outlets. The gases or vapors separated from the original liquid by distillation, and the recovery of whichv is a part of the object of the process, may be separately withdrawn from the several chambers through the upper outlets 25. Instead of using the exterior connections 25 and 26, or either of them, as outlets eX- clusively, either or both may be employed as a means for introducing other fluids required to be heated or to be added to the liquid already in the heater, at intermediate stages of the heating steps.

a It is also part of my contemplation to use as any one or more of the heating units described, a unit having three or more independent sets of passages, as described in my aforesaid patent, and to maintain or circulate in the third, or other additional, set of tubes another liquid or heating medium designed to supply additional heat or to maintain the temperature at a more or less nearly constant degree.

In case cleaning is necessary, any single unit may be opened up for cleaning of the lateral vertical'passages, and such passages cleaned with ease without interrupting the operation of any other units. When the longitudinal passages of any unit need to be cleaned, these can be reached by opening up the end connections and inserting a cleaning tool through the alined passageways of adjacent units if necessary. By longitudinal in this connection I mean the direction in which the alined passages of the whole series of units extend.

It is to be understood that the specific mention in the foregoing specification of certain possible uses of the invention, is not a limitation of the scope in which I claim protection, but, on the contrary, I claim all novel features of the combination here disclosed applied to any uses of which they are capable.

What I claim and desire to secure by Letters Patent is:

A feed water heater comprising a plurality heating units having flow passages for water, and a plurality of intermediate receivers, said units and receivers coupled together in series, and the receivers having larger transverse areas than the sum of the flow passages in the contiguous units, whereby water to be heated is adapted to flow through them progressively and with a slower velocity in the receivers than in said passages, means for separately conducting to the several units heating fluids of respectively difi'erent temperatures, and means for separately discharging from the several chambers matter precipitated therein from the water.

In testimony whereof I have affixed my signature.

CECIL W. STANCLIFFE. 

